EXO-200 is a single phase liquid xenon detector designed to search for neutrinoless double-beta decay of . Here, we report on a search for various Majoron-emitting modes based on 100 kg yr exposure of . A lower limit of at 90% C.L. on the half-life of the spectral Majoron decay was obtained, corresponding to a constraint on the Majoron-neutrino coupling constant of .
DOI:https://doi.org/10.1103/PhysRevD.90.092004
© 2014 American Physical Society
Spectra for the , 2, 3, and 7 Majorons, as well as for the () decays of .
Reuse & PermissionsExample of an energy spectrum fit using data (black points) and corresponding MC simulation. The dotted line shows the MC energy spectrum before the fit, without the detector effects of energy smearing and at the correct energy scale (indicated by the upper scale in red). The continuous line depicts the resulting MC energy spectrum after the fit to the data points. Only SS events are considered in this example. The data and the smeared MC spectra are each normalized to one. The MC spectrum without energy smearing has an arbitrary normalization. The inset shows the ratio of calibrated data to the smeared MC with the linear fit superimposed (black line).
Reuse & PermissionsSS (top) and MS (bottom) data sets and the best-fit models for the case of the Majoron fit. SS energy is predominantly populated by -like events. The most abundant fit component—the decay—is shown in hatched gray. The upper 90% C.L. limits on the number of decays for each of the four Majoron-emitting modes are plotted on the figure all at once, as an illustration.
Reuse & Permissions
